21 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHIMS, AOS of something else?
Leading reported evidence
Check filter and dropping the sump
Suggestion or failed attempt
No successful repair reported for this finding.
0
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0
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Discussions that contain suggestions
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Suggestion
I highly recommend draining the oil, checking the filter and dropping the sump for inspection.
Leading evidence: 'Check filter and dropping the sump' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check filter and dropping the sump' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Suggestion
I highly recommend draining the oil, checking the filter and dropping the sump for inspection.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
21 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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terrible thing has happened to me yesterday, my car is 04 c4s tip, at 6000 rpm suddenly engine started knocking and sound was like lots of metal things are smashing to each other (not very loud). at t the very same moment i looked in to the mirror and saw the cloud of white smoke, there was a lot of smoke. as soon as i saw it i shut off the engine and stopped the car. from starting the strange noise and shutting the engine off was just 1 or max 2 seconds. what do you think if it was an IMS failure is it possible that damage is not huge because it continued just 1 second? or was that something different? perhaps if it was an AOS failure could it make a knocking sound?? car is towed to the porsche center, but they are too busy these days and mechanic will check it after 3-4 days, i will not sleep these 4 days... so what is your ideas? at the moment all i know that engine oil is crystal clear and normal level (but on dipstick, how is on filter i don't know) coolant is in normal level and there is no oil inside. engine oil cap is clear. there are no oil leaks under the car at all. i 'm not able to find out any more details at the moment.. any ideas??
Make sure the shop does not try to start it or they'll cause more damage (they don't care) and it will cost you!
Was it a knocking or screeching noise, like a belt slipping or bearing grinding? If you where close to the car there are some things to look for but it sounds like you just have to wait.
How many miles on the car?
everything happened so quickly that i don't remember exactly sound, as i remember sound was more like bearing grinding and knocking, but wasn't loud it was quite and not aggressive sound
car has 100K miles, and i dont know if IMS was changed or now, i was about to change it
AOS is going to be my first guess, but make sure the
shop does not start
it! I just went through this a couple of weeks ago and thought the worst as the sound was horrific.
thank you for your advice, i will make sure that thay dont start it. hope you are wright and it's AOS. was that AOS in your case?? is it a costly repair if it;s an AOS?
Yes but if you already planned on doing it all together it won't be that bad. See my "Blown Motor" thread Not Blown.
https://rennlist.com/forums/996-foru...ht=Blown+Motor
The noises you've described is not the AOS. Sounds like your engine Fubared itself as the rotating assembly came apart at 6K rpms.
Even if you really did shut it off after only 2 seconds, that's 200 revolutions at 6K rpms ( (6000/60)x 2=200 ). A lot happens in 200 revolutions.
First of all, sorry OP that you're experiencing this failure so soon into ownership. Seems like there have been more and more failure threads these days surrounding the 996 C4S. IMHO, the sounds and other symptoms leads me to believe the outcome is not going to be good. Once they drop the oil sump plate, you'll get the prognosis. I would speculate, based on the sounds, that you've broken a timing chain. Let's hope the engine can be saved regardless.
I hope for the best given the circumstances.
I also have a 04 C4S tip and had the AOS go out. Big cloud of white smoke but I don't remember any noise. Hopefully, you just heard your heart go into overdrive thinking the engine is gone. Thankfully, the guys on here calmed me and it was just the AOS. I'll try to attach the invoice from my indy. I had some other stuff done, but when they dropped the engine some of those 14 year old hoses were brittle and broke.
thank you for your support
Very strange situation, but i'm very very happy
As i said before Mechanics had no time for my car for 4 days, this 4 days were very difficult for me, because i was afraid that it was IMS,... after 4 days of waiting finally came that moment when they started to take it apart. at first they tried to start it, but as i was told here not to start it i asked them to rotate it by the hand at first and it rotated, that was first good sign. after that i gave them permission to try starting it, and it started like nothing happened, for the first few seconds white smoke came out from the exhaust and then is cleared... so nothing was wrong with car, i was in shock, it was very very happy moment
but obviously AOS is not working properly and i am changing it.
also please advice what else should i change to prevent an engine damage, apart from IMS.
also i just can not understand what was that terrible noise from engine if nothing happened?
That's fantastic news. The AOS failure can make a horrific noise.
I am very concerned that your mechanics first instinct was to try and start it. This tells me to look for someone else that has more experience cause they could have cost you a bunch of money ruining your motor!
When the AOS gives up a lot of engine oil, or coolant, or both gets dumped into the intake. When that is sucked into the combustion chambers, it is noncompressible and is sounds like someone dumped marbles in your engine. You may have dodged a bullet because the engine didn't hydro-lock. Hopefully it is just the AOS.
glad to hear you might have dodged a bullet. having owned my 03 4s (1st p-car) for only a few months and not being mechanically sophisticated, when an AOS "fails", what exactly happens to the AOS itself? i understand that oil gets injected into the engine when they fail, but having never seen an AOS i'm uncertain as to what the "failure" is.
thanks in advance
Seems like it would be wise to drop and examine the sump plate and oil filter housing. That will show if there was any damage associated with the horrible noise.
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